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 *     derived from this software without specific prior written permission.
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/*! \file priority_queue.h
 *   \brief A CUDA-compatible, fixed-size priority queue
 */

#pragma once

#include <nih/basic/types.h>

namespace nih {

///
/// A fixed-size priority queue
///
template <typename Key, typename Compare, uint32 SIZE>
struct priority_queue
{
    /// constructor
    ///
    FORCE_INLINE NIH_HOST_DEVICE priority_queue(const Compare cmp = Compare());

    /// is queue empty?
    ///
    FORCE_INLINE NIH_HOST_DEVICE bool  empty() const;

    /// return queue size
    ///
    FORCE_INLINE NIH_HOST_DEVICE uint32 size() const;

    /// push an element
    ///
    FORCE_INLINE NIH_HOST_DEVICE void push(const Key key);

    /// pop an element
    ///
    FORCE_INLINE NIH_HOST_DEVICE void pop();

    /// top of the queue
    ///
    FORCE_INLINE NIH_HOST_DEVICE Key top() const;

    /// return the i-th element in the heap
    ///
    FORCE_INLINE NIH_HOST_DEVICE const Key& operator[] (const uint32 i) const;

    uint32  m_size;
    Key     m_queue[SIZE+1];
    Compare m_cmp;
};

} // namespace nih

#include <nih/basic/priority_queue_inline.h>
